There is a substantial need for security seals that may be manufactured efficiently and economically, and that are easy to use. Many seals are currently available including seals formed of molded plastic in which a hollow body is formed as a single unit with internal flexible fingers for engaging a shackle.
Unfortunately, in order to efficiently mold plastic security seals of this type, the conventional wisdom is that the housing must be open at both ends to enable molding in a single step without the use of collapsible core molding tool members. However, an open housing typically makes it easy to pass a pick or other tool into the housing to disengage the locking fingers that retain the shackle, thereby circumventing the security function of the device.
Various approaches to overcome the shortcomings of molded plastic security seals have been suggested over the years. None are without drawbacks. An early approach suggested in the prior art is illustrated in FIG. 1A. In this design, a closed locking housing 2 is formed with resilient locking members 3 that engage a pin 4. This design is extremely difficult (if not impossible) to manufacture and requires a complex collapsible core molding system which, if implemented on the very small scale typical of many conventional security seals, would be expected to be difficult to operate, to be liable to produce many mis-molded products, and to be subject to substantial manufacturing downtime.
Another example of a prior art design, as illustrated in FIG. 1B, includes an enclosed housing 7 with a separate locking member 6 mounted in the enclosed housing to block the bore of the locking member. Enclosed housing 7 includes an optional metallic cylinder 5 press-fitted into the housing to make it difficult to cut away the rear end of the housing to gain access to the interior of the housing to release the seal. Unfortunately, this design is complicated and expensive to manufacture and assemble. Also, its security function can be compromised by prying member 6 away from housing 5 and receptacle 7 and releasing the shackle, and re-assembling later without any indication that the seal was disturbed.
Yet another prior art approach is illustrated in FIG. 1C. The security seal shown in this figure includes an open bore locking member 8 with one end of the bore closed off by a separate cover 9. Again, this approach is complex, expensive to make and assemble, and can be compromised and re-assembled.
Accordingly, it is an object of the present invention to provide a security seal with a design that can be molded as a unitized device without the use of complex collapsible core mold elements.
It is a further object of the present invention to provide a security seal that is economical to make and easy to operate.
It is another object of the present invention to provide a security seal in which the security function is particularly difficult to circumvent.
Another object of the present invention is to provide a security seal that achieves an engagement that cannot be compromised without either destroying the device or providing an indication that it has been compromised.
Yet another objective of the present invention is to provide a security seal with a locking mechanism having one or more frangible members that will shear away or break if the locking mechanism is breached to help prevent fraudulent reuse of the security seal.
A still further objective of the present invention is to provide a security seal with access-limiting members to thwart tampering.
These and other objects and advantages may be achieved in accordance with the present invention as described below.